En Sat, 15 Mar 2008 11:57:44 -0200, Deepak Rokade <[EMAIL PROTECTED]> escribi�:
> I want to use therads in my application. Going through the docs , I read > about GIL. > Now I am confused whether using threads in python is safe or not. > > One thing I know that if I am accessing global variables in two or more > threads I need to synchronize them > using locking or such mechanism so that only one thread access them at a > time. Yes, altough some operations are known to be atomic so you don't need a lock in that cases. I think there is a list in the wiki somewhere http://wiki.python.org/moin or perhaps at the effbot's site http://www.effbot.org > 1. In order to support multi-threaded Python programs, there's a global > lock that must be held > by the current thread before it can safely access Python objects. > Does this lock need to be held by python application script expliciltly > before accessing any python object or > interpreter takes acre of it ? No, the interpreter takes care of it. The GIL is a concern for those writing extensions using the Python API. > 2. Does multithreaded python script need to held lock before calling any > blocking I/O call? > Or one should not worry about GIL while using python threads if job to be > processed by thread does not call > any global variables and thread unsafe Python/C extension ? Python code should not worry about the GIL. The problem would be, a callback written in Python for a not-thread-aware extension that had released the GIL. -- Gabriel Genellina -- http://mail.python.org/mailman/listinfo/python-list
